Study on the thermal stability of alpha-amylase modified by maleic anhydride copolymer

The thermal inactivation of mesophilic Bacillus subtilis alpha-amylase modified by maleic anhydride/vinyl acetate copolymer has been studied at different polymer/enzyme ratios in the pH range of relevance to enzymatic catalysis. Enzymatic activity measurements combined with circular dichroism measurements were used to determine the enzyme thermostability. The apparent first-order rate constants and activation energies of thermo-inactivation affected by addition of Ca2+ ions as well as by modification have been calculated. The modified alpha-amylase exhibited sufficiently high catalytic activity with enhanced resistance to the thermal unfolding process.